Maria Sharapova withdrew from the Brisbane International with an injured right collarbone Tuesday, shortly before fellow Russian Anastasia Pavlyuchenkova beat 2011 champion Petra Kvitova 6-4, 7-5.

Combined with Daniela Hantuchova's 4-6, 6-1, 7-5 win over No. 5 Sara Errani and the first-round exits of No. 7 Sam Stosur and No. 8 Caroline Wozniacki, the season-opening event featuring eight of the top 10 ranked women had already lost five of its top eight seeds before the end of the second round.

No. 2-ranked Sharapova said she didn't want to risk aggravating a collarbone problem that flared late last month and had also forced her out of an exhibition in South Korea. She was heading to Melbourne to prepare for the Australian Open, starting Jan. 14.

''I still have quite a bit of time to prepare for Australia. I'm on the right track, been training really well, so I just don't want to jeopardize what I've gained in the offseason so far,'' the French Open champion said. ''Just have to make a smart move here.''

Sharapova's absence gives Ukraine's Lesia Tsurenko, the lucky loser in qualifying, a spot in the second round against Australia's Jarmila Gajdosova.

Kvitova, who won the Brisbane title five months before claiming her first Grand Slam crown at Wimbledon in 2011, didn't find any rhythm in her loss to Pavlyuchenkova and will head to Sydney to get some more matches to prepare for the season's first major.

''This tournament was really tough draw and everybody is playing,'' Kvitova said, trying to explain why so many of the top-ranked players were out in the opening rounds. ''After off season it's hard to be on the court against some opponent.''

Third-ranked Serena Williams, who finished off the 2012 season with a 31-1 record including the Wimbledon, Olympic, U.S. Open and season-ending championship titles, was playing Alize Cornet of France in a night match. No. 1 Victoria Azarenka had a first-round bye and was due to open her Brisbane campaign on Wednesday.

On the men's side, local qualifier John Millman, ranked No. 199, advanced to a second-round match with Olympic and U.S. Open champion Andy Murray by beating Japan's Tatsuma Ito 6-4, 6-1.

Seventh-seeded Jurgen Melzer of Austria downed American Denis Kudla 2-6, 6-4, 6-4, while No. 8 Martin Klizan of Slovakia lost 6-1, 6-2 to Uzbekistan's Denis Istomin.

Spain's Tommy Robredo advanced 6-4, 7-6 (4) over American Ryan Harrison and Alejandro Falla of Colombia set up a second-round match with No. 3-seeded Giles Simon with a 6-1, 7-6 (8) win over Jesse Levine.

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